优良降酸酵母菌的筛选及发酵性能

以能够降解L-苹果酸的酿酒酵母FM-cs-08为出发菌株，分别进行紫外诱变和60Co诱变，旨在诱变得到降酸能力显著提高又具有良好发酵性能的酿酒酵母菌。最终筛选得到诱变菌株FM-cs-08-2U，降L-苹果酸比率达到（29.48±0.21）%，比出发菌株提高了（25.44±0.89）%。对诱变菌株FM-cs-08-2U的耐受性及发酵特性进行研究，结果表明该菌株耐受最低pH值为2.5，耐受最高SO2质量浓度为800 mg/L。用FM-cs-08-2U发酵蓝莓果酒，得到果酒残糖量（3.70±0.10）g/L，pH值为3.18±0.01，有机酸含量（8.64±0.02）g/L，酒精度（12.00±1.00）%，结果证明菌株FM-cs-08-2U适合酿造蓝莓果酒。

Strain Improvement of Saccharomyces cerevisiae for Acid Degradation and Fermentation Performance of the Screened Strain

Saccharomyces cerevisiae FM-cs-08, a strain with the ability to degrade L-malic acid, was treated with UV or 60Co γ ray irradiation with the aim to obtain a mutant strain having improved acid-degrading ability and fermentation performance. The mutant strain was named FM-cs-08-2U, by which the degradation efficiency of L-malic acid was (29.48±0.21)%, showing a (25.44±0.89)% increase compared with the starting strain. The tolerance and fermentation performance of the mutant strain were assessed and the results showed that its lowest tolerable pH was 2.5 and its highest tolerable SO2 concentration was 800 mg/L. The residual sugar content of blueberry wine fermented with FM-cs-08-2U was (3.70 ± 0.10) g/L, pH 3.18±0.01, organic acid content (8.64±0.02) g/L, and alcohol content (12.00±1.00)%. These results indicate that the selected mutant strain is suitable for brewing blueberry wine.